The invention relates to the field of computer security and data storage system, and specifically to systems and methods for protecting the integrity and confidentiality of stored data due to inadvertent or malicious operations.
Society's ever-increasing dependence on digital information underlines the importance of protecting data stored in a digital format. Corporations, government, and other professional organizations need to protect their digital assets, since data loss or leakage can directly translate into operational disruption, financial losses, or the loss of irreplaceable cultural and historical artifacts. Even individuals increasingly store valuable digital information, such as personal financial and professional documents, as well as photos, videos, personal letters and other information of substantial sentimental value.
There are many threats to the durability and integrity and confidentiality of digitally stored data, ranging from failure or destruction of storage media and devices, bugs in various parts of the software stack (e.g. device drivers, storage system software, operating systems, or applications), operator error (either intentional or accidental), or deliberate manipulation by malicious intruders or malware running on a machine with access to the data.
Many of these threats can be mitigated by storing data redundantly. For instance, error-correcting codes can mask bit errors, striping or mirroring can mask block or device failures, and backup data copies can enable recovery from catastrophic storage system failures. However, threats from malicious intruders, viruses and worms, software bugs and operator errors may affect all copies of stored data that are on-line and writable. Redundancy alone is not sufficient to mitigate these threats.
To protect the data from such threats, backup copies currently must be maintained in either off-line or write-once storage. Enterprise storage solutions include such archival storage. Typically, data is backed up on tapes that are un-mounted after a backup session. Tape cartridges, magneto-optical and ultra-density optical disks offer a write-once option, offering additional protection for existing data while the medium is mounted. Finally, high-end network-attached storage systems can be programmed to accept only the first write to a given storage block (WORM storage), even though the underlying storage is based on conventional disk drives.
However, individual home users and small businesses often do not have the time, expertise, or budget to take advantage of such advanced solutions. High-end solutions like tape robots and network-attached WORM storage systems are fully automated but too expensive; whereas low-end write-once optical disks and magnetic tape drives are inexpensive, but require diligence and regular attention by an administrator. Moreover, existing write-once storage solutions are expensive to administer for enterprises and waste storage capacity by retaining data for longer periods than needed.